1. Probably quite a few if Jake is any sign. A dude who up till this point was nothing more than a nerd who got bullied, yeah Ella 'helped' but in the end it was mostly his anger and drive that took him forward. Plenty of those who joined HERO be it through their own will or forced will have little choice but to train (if the meeting this update gives us any insight).
2. Those soldiers most likely do not have a month, of course it all depends on when this recruiting effort happened. If it happened recently and I mean within the last week or so (in game) then if the MC has the choice to slaughter them while infiltrating then all the effort in recruiting them was for naught even if they had powers they pale in comparison to MC.
Amber and Liz's dad implies he got his powers recently so I doubt he or other former soldiers had much of any training so yeah for them.
3. Depends, if someone like Jake or a new name (Melody) was out in the field they could easily suggest or 'control' the recruits to follow orders or simply give them the encouragement required to do their job. Or optionally have them there to support the trained officer in charge of the recruits in the field.
4. Realistically even if they attacked around the globe they'd still be outnumbered by not only superhumans on HERO's side but regular trained human soldiers and police. Again, humans can kill level 1s (hell they even made weapons that can take on some of the weaker monsters and I can only imagine they can do damage against a simple level 1 human or level 2 as it could do to MC when he was fighting against Jake and his goons who had those plasma rifles).
The teacher himself talks about how at level 1 humans can kill you but ol Xanthe reinforces the idea that at level 1 (rebirth stage) you are still easily killable
View attachment 2821262
At the end of the day even with their recruitment of former soldiers they'd still be at a disadvantage even more so since humanity is rather...hateful of superpowered peoples after the events of da diamonds where a lot of humans died so I'd expect a lot of currently employed soldiers or cops to go guns blazing against these level 1 soldiers (elite/former) matters not if your out gunned and even more so if another superhuman on HERO's side shows up to assist said human soldiers (rather they want it or not).
It's most def gonna be a massacre at any rate for the humans but SIN's recruits are gonna suffer just as much.